Another intermediate in leucine biosynthesis

Abstract The isolation of β-carboxy, β-hydroxyisocaproic acid, its characterization, and its enzymatic synthesis from α-ketoisovalerate and acetyl COA was described in a previous communication (Jungwirth et al , 1961) . This note reports the isolation of another compound from culture filtrates of a mutant of Neurospora crassa , its enzymatic conversion to α-ketoisocaproic acid, and leucine by extracts of Salmonella typhimurium and Neurospora . The compound has been tentatively identified as α-hydroxy, β-carboxyisocaproic acid.